Female. Compare with my 3 young budgies around the same age as yours, you will see the difference in cere colour. Not one but 3 ceres, all males.
From left to right : Oliver (83 days old), Hestiny (83 days old) and Festiny (76 days old) as at 14Sept2011 .....see pic attached
I've had a single male budgie in the past but have two females now and what a difference in them! My girls are crazy and always up to no good. They surely think they are the bosses of the house. I totally know what you mean. Love my girls to pieces tho.